Stencil-sheet.



FRANK D. BELKNAP, on NEW YORK, N. Y.

STENCIL-SHEET.

1 NIL242. INTO Drawing.

ing is a specification.

My invention comprises an improved stencil and the sheet from which said stencil may be made by operation of an ordinary typewriting machine, or similar agency.

This invention is an improvement upon that described in U. S. Patent No. 1,045,934, granted December 3, 1912, to E. D. Bellrnap and myself as joint inventors, in that it produces a sheet which can be stencilized without previous moistening, and is an improve ment on that described in my application Serial No. 656,851, filed October 24, 1911, in that it produces a sheet of stronger and more durable texture and coating, without sacrificing the ease of stencilizing and the clearness and sharpness of definition of the resulting print, but on the contrary producing a sheet which is more easily stencilized and, more clear cut as to the stenciled characters.-

The underlying novel feature of my present invention comprises the conjoint use of a colloid of vegetable origin, such as Irish moss, and a colloid of animal origin such as animal gelatin as the base of the film forming composition applied to a sheet of thln paper of loose and open texture, so as to saturate and incase the fibers of such paper with and in such material. When a sheet of paper sotreated is operated on by an ordinary typewriting machlne or with a stylus or other device the film of incasing material is forced aside by the type blow or stylus point, forming a stencil across the openings of which the fibers of the paper extend with little or none of the saturating material adhering to them. Through these openings ordinary stencil printing ink will pass, while the remaining portions of the treated paper will prevent the passage of such ink at any other point. The characters impressed on the stencil sheet are then reproduced on a sheet of paper or the like placed under it, and, when a typewriting machine is used in producing the stencil, accurately resemble ordinary typewriting.

In the preferred form of my invention two sheets of very thin Japanese paper known as Specification of Letters Patent. Patented June 23 1914 Application filed May 16, 1913. Serial No. 768,010.

Yoshino paper, are employed, which are simultaneously saturated and coated with the film forming composition. A successful coating of this character for stencil sheets must have the following characteristics: (1) It must be entirely continuous and impervious to ink so that it will not have minute holes which would produce dots on the print made from the stencil. (2) It must be of such degree of softness that the type will cut cleanly and easily through the coating without breaking or tearing the fibers which form the base of the sheet. (3) It must retain this proper degree of softness permanently so that it may be used at any time without remoistening. (4) It must be of suflicient strength to produce an unlimited number of duplicate copies without cracking. (5) It must not be susceptible to ordinary variations of atmospheric temperature. (6) A stencil formed from the sheet must retain its usefulness after long intervals of disuse.

The best method of carrying out my invention and producing the desired stencil sheets at present known to me is as follows: I form a bath composed of the following ingredients in approximately the following proportions: water, 60 ounces; glycerin, 15 ounces; gelatin, 2 ounces; Irish moss, 2 ounces; Monopole soap or soft soap, 2 ounces.

Monopole sea is the commercial name for a material whic is practically a solid form of Turkey red oil, being substantially a sulfo-ricinoleate of sodium, potassium or ammonium, with anhydrids of ricinoleic and sulfo-ricinoleic acids.

The above described bath is preferably formed as follows: The Irish moss in powdered form is stirred into the glycerin cold; the gelatin is dissolved in about twice its weight of cold water, and the soap stirred into the gelatin solution. All these substances are then stirred together and cooked for about half an hour by discharging live steam into the mass until the amount of water of condensation so produced brings the total weight of water up to the proportion given above. The mixture is then strained through cheese cloth and is ready for use. The purpose of the prolonged and violent ebullition produced by the cooking with steam as above described is to thoroughly disintegrate the Irish mossfthe particles of which before use are apt to acquire an exterior tough skin, produced, perhaps, l

by oxidation, and which must be thoroughly dissolved to avoid any lumpiness in thetcoating to' be produced. Two sheets of Yoshino 7 may be next dried by exposure to the atmospherefor a suitable period, and then dipped into a second bath composed of 10 parts by" weight ofcomm'ercial formaldehyde, and 40 parts of water,or it may be dipped in said second bath immediately after treatment by the first bath; As at present advised, 3 I rather prefer the method last described, as it saves time, by omitting the intermediate drying operation, and gives as good, if not better, results, due perhaps to the more complete penetration of the damp'coating film by the formaldehyde solution. I may,

also use 5 parts of glycerin in the second I bath, such glycerin in the second bath tending formed by the first bath, in that it' prevents a diminution of'the' quantity of' ing to preserve the equilibrium ofthe coatglycerin either because it revents the water in the second solution leac ing out the glycerin already in the coating of the sheet by reason of making the second solution a glycerin saturated solution or because the said glycerin in the second bath replaces any glycerin which is removed from the.

coating by such leaching action of the water in the second solution.

. According to my present information the functions of the various ingredients of the baths above mentioned are as follows: The gelatin and Irish moss form the bot y of the film, gelatin giving strength an the moss contributing its great water retaining qualities which produce a permanent softnessand non-drying character in the coatin film. If gelatin alone were used, in, a

su ciently concentrated solution, it would dry out and harden so that the sheet would require moistening before it could be stencillzed. 1

The Irish moss is a natural film or coating producing material. Gelatin isa filler when usedv alone, but when combined with Irish moss it also becomes a coating material.

That'is to say, gelatin dissolved in several times its weight of .water will readily as through a fine sieve, or a. sheet of Yos ino paper, but Irish moss though dissolved in 40 times its weight in water so as to' produce a very dilute solution,-,will not pass "through the sieve or through the Yoshino aper, but remains on the surface as a film.

-- f moss and gelatin are mixed, as .in the formula given above, and made into a dilute solution, both the gelatin and the moss will adhere to'the Yo ino paper and not pass through the same. Consequently, the combination of the two makes'an ideal film forming material for this purpose.

Irish moss produces solutions of much greaterbody or viscosity for a given degree .of concentration than does gelatin. This is probably due to the fact that the dissolved molecules or aggregates are larger, which retards/their penetration of paper or passage through a sieve. This enables a given thickness of coating to be produced with a more completely hydrated solution. The

Irish'moss, also, on account of its fibrousspongy nature absorbs the glycerin and holds it as a sponge will hold water, and also absorbs moisture from the air and'holds it, thus preventing, the coated paper from dryingup with age. t

pure and simple without film forming or body formin capacity. The Monopole soap is both a so tening agent and an ink repellent. The formaldehyde serves to coagulate and set both the gelatin'and the Irish moss, and also preserves themagainst decay and disintegration. v v Monopole soap has certain practical advantages over the castile soap mentioned as the preferred form of soap ,in the formula Glycerin 1s a tempering or softening agent given in my prior application, Serial No.

695,309, filed-May 4, 1912, in that it has greater solubility in water, a greater softness (without stickiness) when dry, and a greater power of holding glycerin 1n the composition. This makes it ossible to produce 'sheets'for stencili ng w ich are softer than those produced by theformula of my said prior application, by reason of their containing more glycerin, without danger of their becoming sticky. This. capacity of Mono ole soap for holding greater quantities o glycerin I'believe to be due to the fact that it is of a more colloidal character,

than ordinary soap, having constituent molecules of larger size.

strength without interfering with the ease and cleancut quality of the stencilizing action of the type. The use of two thin sheets gives greater strength than is possessed by a The double sheetsof thin paper give great single sheet of paper of the thickness equiva-' lent to that of the doubled sheet. This is doubtless due to the crossing of the two sets of fibers, and to the greater-compactness of structure of the thin sheets, as comparedwith a sheet of double the thickness. At. the same time the very thin sheets are easily penetrated by the glycerin and perhaps other constituents of the: solutions forming the bath and a body of the cementing materials 1s formed between the sheets, where it is preserved from'excessive dryingand exerts a permanent softening action on the fibers of the sheets themselves, thus insuring ease of stenciling. Whatever the reasons may be I have demonstrated by practical test that stronger and better stencils are formed of such double sheets than from a singlesheet 0111f thickness equal to that of such double s eet.

While stencils may be formed of single sheets treated with the materials above described. the best results are produced by using the double sheet and the formulae above given are especially designed to work with the double sheets. Thus the large proportion of glycerin used in the first bath might tend to render the'surface of a single sheet too sticky, but when the film containing such large proportion of glycerin is partly incased between the two sheets of paper its stickiness serves only to cement them together, and. does not injuriously afiect their exterior surfaces.

Variations in the proportions above given can be made within limits to meet the requirements of special cases without departing from the underlying principles of my invention.

Having, therefore, described my invention, I claim 1. Asheet capable of being stencilized by printing type without the external application of moisture comprising a thin, loose fibered sheet of paper treated witha solution containing gelatin, glycerin, Monopole soap and Irish moss.

-2. A sheet capable of being stenciled by printing type without the external application. of moisture, comprising a thin, loose fibered sheet of paper treated with solutions containing gelatin, glycerin, Monopole soap, formaldehyde and Irish moss.

3. Asheet capable of being stencilized by of very thin, loose fibered paper treated sov with a solution capable of being displaced by pressure of printing type after being exposed to the atmosphere and without the application of external moisture, said sheets being superimposed and cemented together by the said solution.

5. A stencil blank comprising two sheets of very thin, loose fibered paper treated with a solution containing animal gelatin, Irish moss and gylcerin, said sheets being superimposed and cemented together by said solution.

6. A stencil blank comprising two sheets of thin Japanese Yoshino paper treated with solutions containing animal gelatin, 3. vegetable colloid, glycerin, soap, and formaldehyde, said sheets being superimposed and oemented together by the cementitious components of such solution.

7. A stencil comprising a thin sheet of loose fibered paper treated with a solution containing gelatln, glycerin, Monopole soap and Irish moss.

8. A stencil comprising a thin sheet of loose fibered paper treated with a solution containing gelatin, glycerin, Monopole soap,

Irish moss, and a coagulant.

FRANK D. BELKNAP.

Witnesses:

S. WEINBERG, M. FILEs. 

